Broaching mechanism.



'30 The invention nNiT-ED STATES I ATENT RALPH a. LAroINTE,l or HUDSON, MASSACHUSETTS, ASSIGNOE, BY MESNE ASSIGN- MENTS, To LAPOINTE MACHINE Toot. co., or HUDSON, MASSACHUSETTS, Aconro- RATION 0F MAINE.

BHOAGHING MECHANISM. g

Specification .of Letters Patent. Patented June 4, 1912.

Application filed October 4, 1911, Serial No. 652,880.`

Be it known that 1, RALPH R. LAroINTE, a citizen of the United States, and resident of Hudson, county. of Middlesex, Commonwealth of Massachusetts, have invented an Improvement in Broac-hing Mechanism, of which the following description, in'connec- -tion with the accompanying drawings, is a specification, like letters on the drawingsn representing like parts, p

This invention relaties to broaching mech-v anism, and while having other and more general fields -of usefulness, is especially adapted for the-broaching out of key ways inl the shaft holes of pulleys, gears, and other wheels. A.

The invention provides an improvedv broach' and a novel form .of guide sleeve thereforand work supporting arbor whereby guided in its slide'ways with a virutal elimination of all chattering orback lash.

The improved formofbroach is designed to enable the cuttingfpf opposite-key ways in the work when desire'd,;the.broach in this operation being. balanced as 'to the thrusts;

imparted by the opposite cutting ribsl so that frictional lresistance and wear is minimized. i l l v further has. todo with a novel form of guide sleevefor the .broach and work arbor which can` be easily and cheaply manufactured, and assembled in I vthe machine or taken apart as required very readily, and without disturbance of other The invention willbe better understood from the following detailed description, taken in connection with the accompanying.

drawings, and will be thereafter. pointed out in the appended-claims.

Referring to the drawings, Fi-gure'1 a side elevation showing. the improved mecha- .nism set in place in a broaching machine head, a portion of such head being yshown conventionally.v Fig. 2 1s a transverse section through thebroach, the built upv guide.

sleeve beingshown in end elevation. Fig. 3

s is a section on line 3-3 of Fig.4 2 with the broach removed. Fig. 11 is a view similar to Fig. 2, showing a modified form of the invention, and Fig. 5 is a transverse section showing the broach as integral.

*The head ofthe broaching machine is shown conventionally atlO with the usual the broach is vclosely and accuratelyring 17,

vinto the aperture ously cutting opposite in the sleeve arbor and circular aperture 11 in its end to receive the sleeve arbor yfor guiding the broach and supporting the work. This sleevel arbor has 1in, the machine head with a flange 13 adapted resistl the cutting thrusts, and an arbor'14 over which t-hepulley, or otherwheel to bel suitable backing shoulder ,14a to serve as a backing abutment for the work. The sleeve arbor 1Q inthe present instance is built up of assembled parts, the sleeve proper which guides the broach being formed in two halves 15, 16 with the line of division indicated at 16. The sections of this sleeve are drawn and held rigidly together by a heavy integral ring 17 having a conical 'aperture 18 therethrough adapted to engageacon'rcal formation 19 on the lsleeve sections and the parts being rigidly fixed together by a thimble20 threaded over projecting ends '21 of to. bear thereagainst' to' -a cylindrical po-rtion 12 adapted to `fit the 1 .opening 11 .operated on, vis fitted, this arbor having a the sleeve sections and engaging against the The rin-g 17 carries the cylindrical before referred to, and -fitting portion 12, I

of. the machine head and also the flange 13 for engagement with the endof said'head. As seen in Figs. 1, 9., and 3 the apparatus 1s adapted for lsimultanekey ways 1n the work,

and. the.work receiving arbor 14 is hence slotted at opposite the projection ofl its cutting portions therefrom.

An important feature of the invention has to. do with the improved broach and this consists in a bodyT portion 22 of rectangular form and relatively heavy stock with lscrrations as seen at 26, 27, but when only one key way is desired, one of the ribs, as 23, only extends al short-distance out from` the body of the broach so as to perform its guiding Aand alining function by engage! ment with the walls of its slot 21.

In Figs. 1 and 9. the broach is shown with a construction'permitting'a second cutting sides as seen at 21 to guide the double ribbed broach and permit 'portionto be applied orfnot as desir'ed.- In` l this form the rib 24 has-its teeth 28 formed In the form of' he invention shown in Fig'. 4 the broach is mounted eccentrically, the guide Way 25 for the body'22 of the .broach being to one side of the center of the arbor 14 so that` While the teeth. of t-he rib 24 extend outward beyond the circumference' ofthe-arbor 14, the -,opposite rib 23 is only adapted f orfits. guiding function. In the case ofbroaches designedl foruse with this form of the invention only,of course any 'special'formation ofthe rib 23 to receive a cutter bar ,is unnecessaryy and may be omitted. In the form of the invention shown in Fig. 5 both of the oppositeV ribs carry cutting teeth integral with the rib, this form being preferable Where only opposite key ways' are to be'formed, While the form `of Eig. 2 is especially adapted for use lWhere diierent -sizes ofwork are fre-'- quently encountered and'ivhere it is desired to dispenselwiththe necessity for changing breaches, `lvi'lhe broach may be operated in any usual ondesired manner being shown asconnectedgto screw 32 for .rec1procat1on, the-. construction of the operatlng mechanism br' ofthe machine support forming no part of the p resent invention. The .sleeve arbor thus formed can. be quickly and easily assembled in-place in the machine, or taken apart as required, and

. when assembled is practically as rigid as an integral structure.' A further advantage 'of `this .form is that the sectional construction lof the lbroach guiding portions enables the 'parts to be machined and finished more' readily than is the casetwith an integral sleeve. The broach with a body of rectangular form and oppositely extending ribs is adapted to be closely guided in the way 25 and the slots 21 so that key Ways may be very accurately produced and in the case of the double sided broach the cutting thrusts from. the opposite ribs are substantially balanced so that there is practically no frictional resistance and very little Wear on the bearing surfaces.

By reason of the laterally extending guidelledges which are afforded bythe enlarged body of the broach, it is held up and accuratelv guided on the return stroke so that the 'teeth do not drag over the Work. This .is a feature of importance, slnce thedragging of the teeth on the return would not only be apt tov mar the work, but would unnecessarily Wear the teeth themselves.

Having describedmy invention, what I claim as new, and desire to secure by Letters Patent is: i

"1. An apparatus of theakind described, comprising av sleevearbor for guiding a broach and supporting the Work thereon,

said arbor being formed of plural sections,4

and means for rigidly-clamping'said sections in assembled relation, said means having a Vportion adapted to lit a breaching machine head.

2. An apparatus of the kind described, comprising a sleeve arbor formed in plural sections with alengthwise extendingguide- 'way therein for a broach, said arbor having a shoulder to serve as a Work abutment, and

means cooperative with. a portion of thel arbor at the rear of said shoulder for clamping the sections thereof rigidly together in assembled relation. j

8. An apparatus of the kind described, comprising a sleeve arbor having a length- Wise extending guide way therethrough. for a broach, a-slotted Work holding portion at its front end, and'a shoulder to serve as a lWork abutment with a conical. formation at the rear of said shoulder, and a ring hav.- ing a tapered opening.therethrough for cooperation with said conical formation to clamp the sections rigidly together, said .ring being formed to interengage With abroaching machine head.

j 4. An apparatus of the ,and described,

.comprising a sleeve arbor having a length- -W1se extending angular guideway there# through for a 'broach and slots at opposite sides of said guide way opening thereinto, a broach having a body angular in cross section -to tit said guideway with oppositely eX- tendingribs to fit said slots -'and be guided thereby, the body .of the broach having bearing shoulders at either ,side of vsaid ribs litt-ing slidably against backing portionsof said a'rbor,.and a line of cuttingteeth tapering with relation tothe direction of broach 'movement carried by one of said ribs.

5. An apparatus of the kind described, comprising a sleeve arbor having-,al length- Wise rectangular guide Way therethrough fora broach and slots at opposite sides openingint-o said Way, and a broach having a body portion rectangular in cross section to 'fit said way and'oppo'site ribs to be guided by said slots, the body of the bro'ah having bearing shoulders at eitherside of saidl ribs fitting slidably -against backing portions of said arbor, said ribs having lines of cut-ting teeth formed thereon oppositelydivergi'ng with relation to the directionof broach movement and operable through a work holding portion of said sleevearbor for cutting key Ways in a Work piece.

g 6. An apparatus ot the kind described,

l comprising a sleeveV 'arbor with a Work '10 said ribs -itt-in'g slidably against backing` l ,portions of said arbor, one of said ribs havinga line` of cutting teeth 'formed integral holding portion at its front end, said arbor having a lengthwise extending angular guide Way therethrough for a breach and slots extending oppositely from said Way, and a breach having an. angular bodyto lit said guide Way and opposite ribs yto be guided-by said slots, the body'of the broach having bearing shoulders at either side of therewith, and the other of said ribs being -of lesser Width and having a bar with another line of cutting teeth removably xed thereto, said lines of cutting teeth divergingr4 oppositely from the line of breach movement.

j In testimony Whereo, I have signed my name to this specification', in the presence of two subscribing Witnesses.v

RALPH R. ,LAPOINTE Witnesses:

" C. L. ROGERS,

R. G. lnliinsmr.v 

